Physiological regulation in infants of women with a mood disorder: examining associations with maternal symptoms and stress

The offspring of mothers with mood disorders may evidence increased behavioral problems as early as preschool; however, no study to date has examined psychophysiological characteristics during infancy, particularly among offspring of mothers diagnosed with bipolar disorder. Elucidating psychobiological mechanisms of risk early in development is critical to inform prevention and early intervention efforts.

This study compared physiological and behavioral responsivity in 6-month-old infants (N = 329) of mothers with lifetime histories of bipolar disorder (BD, n = 44), major depressive disorder (MDD, n = 244), or no history of Axis I disorders (CTL, n = 41). Infant respiratory sinus arrhythmia (RSA) was measured in a laboratory stressor paradigm. Measures of infant affect and behavior during mother–infant interaction, current maternal depressive symptoms, and exposure to stressful life events were examined with respect to diagnostic group and RSA.

Groups did not differ in baseline RSA or infant affect measures. However, during the stressor task, infants of mothers with BD evidenced increases in RSA, while infants of MDD and CTL mothers evidenced decreases in RSA. Though levels of postnatal stress and current levels of maternal depressive symptoms differed among groups, neither of these factors predicted infant psychophysiological responses.

At 6 months of age, infants of mothers with BD show differences in psychophysiological regulation. These differences cannot be accounted for by perinatal outcome, current maternal depressive symptoms, or exposure to stressful life events, and thus may reflect endophenotypic markers of psychopathological risk.